Firmware 3.0 Beta 5 (7A312g) and iTunes 8.2 are seeded to developers. Apple breaks its tradition of seeding betas every other week and releases Beta 5 after only 8 days.

Could this early release be in anticipation of Leopard 10.5.7 update rumored to be on track for this Friday? Maybe a compatibility update?

Downloading now. Will update with changes.

EDIT: Upgraded store kit is the only api updated.

There is a new iTunes 8.2 and it apparently the option+click/shift+click has been patched. If you want to keep your cellular data settings screen, tethering, and MMS then make sure your carrier settings (ipcc) is updated before you upgrade.

Known Issues
• A small set of AT&T customers may experience data services that stop working
after installing iPhone OS 3.0 beta 5 on a device. If you experience this problem
with a device that worked properly before the beta 5 update, please call the
developer support line at 1-800-xxx-xxxx for help restoring data services.

This may be more of a loop hole patching update rather than a bunch of new features.
EDIT 2:

YOU DO NOT HAVE TO USE THE NEW ITUNES TO UPDATE TO BETA 5! I RECOMMEND USING THE OLDER ONE SO YOU CAN UPDATE YOUR IPCC!